Automatic telephone exchange system



Nov. 25, 1930; F. TRAcHsEL AUToMATlc TELEHONE EXCHANGE SYSTEM FiledApril 1.2, 1926 2 Sheets-Sheet l gill.

Nov. 25, 1930. F. TRACHSEL v AUTOMATIC TELEPHONE EXCHANGE SYSTEM FiledApril l2, 1926 2 Sheeis-Sheet 2 Patented Nov. 25, 193() UNITED STATESFRITZ TRACHSEL, 0F BERNE, SWITZERLAND, ASSIGNOR TO CHR. GFELLER AKTIEN-GESELLSCHAFT, OF BERN-BUMPLIZ, SWITZERLAND A PATENT ori-ICE AUTOMATICTELEPHONE EXCHANGE SYSTEM Application filed April l2, 1926, Serial No.101,516, and in Switzerland April l5, 1925.

This invention rela-tes to automatic telephone exchange systemsk andprovides an im.- proved construction or arrangement ota pilot switchused in such systems comprising selecting devices located in theexchange and adapted to operate automatically under the control ofinterrupters or selector discs Which forni part ofthe subscribers setsand which are operated bythe calling subscribers.

According to the invention the exchange comprises a number of similarswitching devices (one for each subscriber) adapted to be operatedselectively by an operating inember having a step-by-step movement andlso arranged and connected that the switching devices'ofthe calling andcalled subscribers are first moved into a position ot readiness underthe control of the calling subscribers set and arejthen operatedautomatically by the movement of the operating device so as to eftectthe requisite connections between the called and the callingsubscribers.

Y In order that the invention may be more readily understood referenceWill now be made to the laccon'ipanying drawings 1n which Fig. l is anelevation showing the arrangement of a bank of switching devices,

Fig. 2 is an end elevation in Which only one magnet M39 is shown7 Fig. 3is a partial top plan view of one of the switching devices,

Figs. 4, 5. vand 6 are enlarged detail views,

Fig. 7 is an enlarged detail view of one of the rods or blades Si?,

Fig. 8 is a diagram ,of the parts used in a single pilot switch.

As shown in the drawings the exchange comprises a number of mechanicalswitching devicesV (one foreach subscriber) arranged one above theotherr and each comprising tvvo horizontal sliding rods, Zn and Zw", F3. adapted to operate a number of sets of spring contacts.

The spring-'contacts are arranged in vertical rows mounted'on insulatedsupports m. For each subsc 1iber there is provided one set of contacts ooperated by a cranked end e of the rod Zai' one set of contacts woperated by one end ot the rod Zu and several sets of contacts du whichare operated by projections z provided on strips or tongues' H6', H62,attached to spring strips ,t' fixed on the supports m.

As shown in Figures 2 and 4f each set of contacts du comprises eightspring strips constituting four contact points which are arranged inpairs on either side ot' the rod Zu, the contact points above the rodZu', Fig. 2, being operated by the tongue H62 Whilst the contact pointsbeloiv the rod are operated by the tongue H6. For each pair of tonguesH6 andv H62 there is provided on the rod Zu a collar or abutment Mz"adapted to engage and move the tongues H6 and H62 as hereinafterdescribed. The rod Zu2 is provided With similar colla-rs or abutmentsMv? adapted to be engaged and moved by` the tongues He', H62 to move therod- Zag in a. direction to open the contacts p.

The rod Zu is provided With an armaturel An controlled by anelectro-magnet M Which is adapted to move the rod against the action ofthe spring strips ,t from the position shown in Figure 3 towards theposition for closing the contacts du. For each set of contacts duprovided for one subscriber there is a vertical sliding rod St', S62, orStg 'in the form ofa flat strip having lateral projections No struck outfrom the strip adjacent one edge and adapt-ed to engage the free ends ofthe strips H6", H62. In the normal position of the strips He', H62 shownin Fig. 3 the free ends thereof are clear of the path of movement of theprojections No but When any of the rods Zu" is moved by lits magnet Mtowards the position for closing the contacts Zu the free ends of thecorresponding strips He H62 are moved into the pat-h oi movement of theprojections No so that by theven tical sliding movement of one of therods St', S152, Sts` one. of the strips H6", He2 provided for theselected subscriberv can be engaged and moved by one of the projectionsN 0 so to effect closure of the corresponding contacts du. The strip H6or H62 also moves the rod Zt by engaging one of the abutinents Mi? So asto break the contact between the spring contacts p. The parts are soproportioned that although thexnagnet M' is capable 'of moving the rodZu against the action oi' the springs trips f suiiiciently to close thecontacts fw, none ot the-contacts 'du or p, are aii'ected until one ofthe strips He, H62 is engaged and moyed by a projection No. rTheposition A o'a strip He after being moved by a projection No is showninv dotted lines in Fig. of the drawings. 'f

Each ofthe vertical rods S', S152, S253 is l@ adapted to be moved fromits lowerniost to its uppermost position stepV by step by means of apawl KZL" adapted to engage ratchet teeth provided on the rod andcontrolled by an electro-magnet H and armature A70 and so .3 arrangedthat when the electro-magnet H `de-energizned thepawl lili `is .out ofengagement with the ratchet teeth on the rod as shown inV 2; Downwardmovement loit the rod during the intervals between succesgg siveoperations ci the pawl lila" is normally pr vented by means of a pawl KWcontrolled by a spring Fe which is capable of moving the pawl into twopositions of equilibrium in one of which it tends to engage ratchetteeth formed-0n the rod as shown'in Fig. 2, whilst in the other positionit is outof contact with therod. rlwo stops g, g2 are iixed on the lowerend of the rod andare adapted to act on a lever or projection iiXed tothe pawl KW, so as shown in Figure 2 so that when the rod reaches itsuppermost position the projection g moves the pawl KW out ci engagementwith the rod and permits the latter to fall by gravity intoitslowerinost position and to act upon the pawl KW by means of a strip g2so as to restore the pawl Klz'2 to the position shown in Figure 2. Y YEach of the rods S, S222, Stg has contact arms or brushes Kfclco-operating with rows of contacts K'clg and constituting a pilotswitch. lThis pilot switch is only diagrammatically indicated in Figuresl and l2 of the drawings but-is more completely shown in Figure 8. Y. tcomprises four contact arms I, ll, 1H, IV, each of which co-operateswith a separate rowof contacts. The contact arms l, Il, HI, lV, movetogether in the example .shown vin the drawings through` fourteensuccessive positions corresponding to fourteen successive positionsprovided :tor by the pawls KZ/i, KZ?? and their ratchet teeth. ln eachof these positions, each of the contact arms l, ll, Ill, IV bridges twoadjacent contacts, certain of which are numbered in Figure 8.

FVhile Figure i 'shows a plurality of the pilot switch mechanisms usedin this invention, assembled sideby side to constitute an exchangesystem, it will be understood that this duplication of the switchelements` is to simply to provide simultaneous service to number oi'subscribers. The invention 'claimed in this application relates moreparticuiarly to the design and construction of anyone pilot switch,adapted to selectively t5 operate under the controlof a subscribers usedwith that subscribeiand moved by-hi-s selector disc, common to all suchsystems, to effect a selective control of speaking circuits co-nnectingtwo stations.

Generally speaking, the operation of any one of the pilot switches maybe described as follows:Y n

Vhen a calling subscriber lifts Vhis telephone, one of the magnets M,say M30, Figure 3, is energized. rlhis causes armature Aam to move rod.Zu a certain distance suiiicient topset one ofV the tongues l-lfe, orH62, sidewise and cause it to be mechanically engaged by the camprojection No on the appropriate selector rod St etc.v This initialmovement of thev rod Zu is only suicient in extent to 5.3 close contactfw, which edects a connection Y with the calling subscribers line, allcontacts du remain open and Contact p remains'closed. Further movementor' rod Zu can only be effected by manipulating the selector rod Str',

selector disc through theagency of a magnet H, the detailed operation ofwhich has been described above.

This further movement oi' rod Zu takes 90 piace because of theengagement of one of the projections No withv one of the tongues He', orH62, the up and down movementor" the selector bar, carrying theprojectionV No, causing the latter toimpart a sideways thrust to rod Zuwhich closes-one oi thedw contacts .and opens contact p, the edect ofopening the last named contact being to isolate that'particularselector, or pilot switch from calling operation. It will thus n be seenthat each switch velement initially can be energized by a callingsubscriber to automatically effect aV selective line connection with thecalled subscriber. Y

Summarizing certain essential features f 4disclosed by the pilot switchof th-isjinvention, it will be found that the contact y), Fig. 8,provides an elementl designed to impress.

'on the switch mechanism an initial selective setting of the switchparts which places it in @prie communication with the line of thesubscriber called, through contact fw. After this stage of the switchoperations, the selector bar appropriate to the desired subscriber isbrought into play to eii'ect a further selective setting among thecontacts du, which will be determined by his call number, the completionof this operation will result in aspeaking connection having been madeautomati-A cally by the switch. ln practice,it will be understood thatboth subscribers will be provided with at least one of thepilot'switches described.

`What l claim is 1. In a switch for an automatic telephone exchange, aplurality of spring contacts placed side by side, cams mounted adjacentsaid spring contacts, means adapted to'eect a successive piural stagemovement of said cams, comprising a slide bar under magnetic pluralityof operating other bars transversely movable With respect to said slidebar by magnetic means, one of which is designed to engage said cam andmore it from selective position to contact closure position ofitsassociated spring contact.

3. ln a telephone exchange switch mechanism, a series of spring contactsplaced side by side, cam for. closing said contacts, in

. combination with a slide bar. under magnetic control designed to setsaid cam to a preliminary closure position, other bars, magneticallyoperable at right angles to said slide bar and provided with means toselectively engage said cam when placed in said preliminary closureposition7 and ak second slide bar movable parallel to said first slidebar under the selective control of said cam to open one of said spring'contacts.

4. In an automatic telephone switch, a series of spring contacts placedside by side in combination with a plurality of parallel sliderods eachprovided With Yselectively spaced tappets, and means for causing saidtappets to close and open certain of said spring contacts through a stepby step movement of said rods.

n testimony whereof I affix my signature.

FRITZ TRACHSEL.

